As a pump control unit configured as above, PTL 1 shows a sensor-less, three-phase brushless DC motor for driving a hydraulic pump and discloses a control device having a microcomputer-controlled motor driving IC and an FET circuit controlled by this motor driving IC. The control device disclosed in this PTL 1 includes a unit rotational angle detection circuit detecting rotation of the electric motor and providing the detected rotation to the motor driving IC and a power current detection circuit detecting a current value fed to the electric motor (excitation coils) by a shunt resistor through the FET circuit and feeding the detected current value to a microcomputer.
According to PTL 1, the microcomputer effects a PWM calculation and result of this calculation is given from the motor driving IC to the FET circuit to set a duty ratio, according to which control of rotation of the electric motor is executed.